Math.sin() is slow. Using a lookup table for sin/cos is roughly 50x faster. The loss of accuracy is minimal, maximum error is roughly 0,001. You can probably get away with it.
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| public static final float sin(float rad)
{
return sin[(int) (rad * radToIndex) & SIN_MASK];
}
public static final float cos(float rad)
{
return cos[(int) (rad * radToIndex) & SIN_MASK];
}
public static final float sinDeg(float deg)
{
return sin[(int) (deg * degToIndex) & SIN_MASK];
}
public static final float cosDeg(float deg)
{
return cos[(int) (deg * degToIndex) & SIN_MASK];
}
private static final float RAD,DEG;
private static final int SIN_BITS,SIN_MASK,SIN_COUNT;
private static final float radFull,radToIndex;
private static final float degFull,degToIndex;
private static final float[] sin, cos;
static
{
RAD = (float) Math.PI / 180.0f;
DEG = 180.0f / (float) Math.PI;
SIN_BITS = 12;
SIN_MASK = ~(-1 << SIN_BITS);
SIN_COUNT = SIN_MASK + 1;
radFull = (float) (Math.PI * 2.0);
degFull = (float) (360.0);
radToIndex = SIN_COUNT / radFull;
degToIndex = SIN_COUNT / degFull;
sin = new float[SIN_COUNT];
cos = new float[SIN_COUNT];
for (int i = 0; i < SIN_COUNT; i++)
{
sin[i] = (float) Math.sin((i + 0.5f) / SIN_COUNT * radFull);
cos[i] = (float) Math.cos((i + 0.5f) / SIN_COUNT * radFull);
}
for (int i = 0; i < 360; i += 90)
{
sin[(int)(i * degToIndex) & SIN_MASK] = (float)Math.sin(i * Math.PI / 180.0);
cos[(int)(i * degToIndex) & SIN_MASK] = (float)Math.cos(i * Math.PI / 180.0);
}
} |
